1.25GB isn't enough for most recent games at 1080p.
Get the 2.5GB one, Max Payne 3 really eats up VRAM if you set it with a lot of MSAA and stuff.
I have my 570 2.5GB for almost 1 year,and it's really good at any game at 1080p.
SLI with the 1.25GBs is nice for multi monitors, but the lack of VRAM would be really annoying.
BTW, I use the single 570 with SoftTH to play some games on 3 monitors (two 17" and a 23"),and it works really well.